The article “Chronic Beryllium Disease and Sensitization at a Beryllium Processing Facility” (K. Rosenman, V. Hertzberg, et al., Environmental Health Perspectives, 2005:1366–1372) discusses the effects of exposure to beryllium in a cohort of workers. Workers were categorized by their duration of exposure (in years) and by their disease status (chronic beryllium disease, sensitization to beryllium, or no disease). The results were as follows:
Can you conclude that the proportions of workers in the various disease categories differ among exposure levels?
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